Definition and background:
The Spanish term for ornament or embellishment. Originally, Embellishments introduced in French music of the 17th century typically in keyboard music.See also [Eng.] Ornament; [Fr.] agr'ments or [Fr.] broderies; [Ger.] Verzierungen; [It.] fiorette or [It.] fioriture or [It.] abbellimento; [Sp.] adorno.Also ornamentation; embellishment.
For more information on the music term "Adorno" check out these other resources:
Wikipedia - Glossary of Musical Terminology
Virginia Tech Multimedia Music Dictionary
ORB -- Medieval Music Glossary